JP2012221098A - Coordinate detection device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coordinate detection device and a display device capable of improving capability for coordinate detection.SOLUTION: A coordinate detection device is configured to respectively calculate a first value (ΣC) as the total sum of the capacitance values of first electrodes of a plurality of electrode rows, a second value (ΣL) as the total sum of the capacitance values of second electrodes of the plurality of electrode rows, a third value (ΣR) as the total sum of the capacitance values of third electrodes of the plurality of electrode rows, and a fourth value (ΣLCR) as the sum of the first value, the second value and the third value, and to, when the second value is larger than the third value, detect first position coordinates on the basis of a first capacitance ratio ((ΣC-ΣL)/ΣLCR) as the ratio of a difference between the first value and the second value to the fourth value, and to, when the second value is smaller than the third value, detect the first position coordinates on the basis of a second capacitance ratio ((ΣR-ΣC)/ΣLCR) as the ratio of a difference between the third value and the first value to the fourth value.

Description

  The present technology relates to a coordinate detection device and a display device that detect a position coordinate of a detection target based on a change in capacitance.

  In recent years, electronic devices that detect the position of a finger based on a change in capacitance and control the display of a screen or the operation of the device have become widespread. As this type of capacitance sensor, a method of detecting a change in capacitance of each of a plurality of electrodes arranged in a plane and determining an input position based on contact or proximity of a finger in the plane is common. is there.

  For example, Patent Document 1 describes a coordinate input device including a detection electrode pair composed of one detection electrode and the other detection electrode having the same outer diameter. Each detection electrode has a plane shape of a substantially right triangle, and is arranged such that each hypotenuse faces each other, whereby the width of one detection electrode is reduced along the first direction, and the other The width of the detection electrode is increased along the first direction. A plurality of pairs of the detection electrode pairs are arranged in a second direction orthogonal to the first direction, and the coordinate input device detects the coordinates of the input position based on the capacitance change of each detection electrode.

  In particular, the coordinate input device is based on the ratio (ΣCL / ΣCR) of the sum (ΣCL) of the capacitance change amounts of one detection electrode and the sum (ΣCR) of the capacitance change amounts of the other detection electrode. An input position coordinate along one direction is calculated.

JP 2008-269297 A

  However, in the method of detecting the input position coordinates based on the ratio between the capacitance change amount of one detection electrode and the capacitance change amount of the other detection electrode as described in Patent Document 1, the method follows the first direction. The linearity of the coordinate detection value with respect to the finger position is poor, and accurate coordinate detection is difficult.

  In view of the circumstances as described above, an object of the present technology is to provide a coordinate detection device and a display device capable of improving the performance of coordinate detection.

In order to achieve the above object, a coordinate detection device according to an embodiment of the present technology includes a plurality of electrode arrays and a processing unit.
Each of the plurality of electrode rows includes a first electrode, a second electrode, and a third electrode. The first electrode extends in a first direction, and a first region in which a dimension parallel to a second direction orthogonal to the first direction is gradually increased with respect to the first direction; And a second region whose dimension parallel to the second direction is gradually reduced with respect to the first direction. The second electrode extends in the first direction, opposes the first region and the second direction, and a dimension parallel to the second direction with respect to the first direction is gradually reduced. Become. The third electrode extends in the first direction, opposes the second region with the second direction, and is gradually larger in dimension parallel to the second direction with respect to the first direction. Become. In the plurality of electrode arrays, a set of the first electrode, the second electrode, and the third electrode is arranged in the second direction, and the capacitance is increased according to the proximity of the detection target. Configured to change.
The processing unit includes a first value that is a sum of capacitance values of the first electrodes in each of the plurality of electrode rows and a sum of capacitance values of the second electrodes in each of the plurality of electrode rows. A value of 2; a third value that is a sum of capacitance values of the third electrodes of each of the plurality of electrode rows; and a sum of the first value, the second value, and the third value. The fourth value is calculated. When the second value is greater than the third value, the processing unit has a first ratio that is a ratio of the difference between the first value and the second value and the fourth value. The first position coordinate is detected based on the capacity ratio. When the second value is smaller than the third value, the processing unit is a ratio of a difference between the third value and the first value and a fourth value. The first position coordinate is detected based on the capacity ratio.

  In the coordinate detection device, when the second value is larger than the third value, based on the first capacity ratio, and when the second value is smaller than the third value. Are configured to detect the first position coordinates based on the second capacity ratio. Thereby, since the linearity of the coordinate detection value along the first direction can be satisfactorily obtained, the detection accuracy of the first position coordinate can be improved.

A coordinate detection device according to another embodiment of the present technology includes a plurality of electrode arrays and a processing unit.
Each of the plurality of electrode rows includes a first electrode and a second electrode. The first electrode extends in a first direction, and a dimension parallel to a second direction perpendicular to the first direction with respect to the first direction is gradually increased. The second electrode extends in the first direction, faces the first electrode in the second direction, and is gradually smaller in dimension parallel to the second direction with respect to the first direction. Become. The plurality of electrode arrays are configured such that a set of the first electrode and the second electrode is arranged in the second direction, and the capacitance changes according to the proximity of the detection target. The
The processing unit includes a first value that is a sum of capacitance values of the first electrodes in each of the plurality of electrode rows and a sum of capacitance values of the second electrodes in each of the plurality of electrode rows. A value of 2, and a third value that is the sum of the first value and the second value are calculated. The processing unit calculates a first position coordinate of the detection target along the first direction based on a ratio between the difference between the first value and the second value and the third value. To detect.

  In the coordinate detection device, the first position of the detection target along the first direction based on a ratio between the difference between the first value and the second value and the third value. Coordinates are detected. Thereby, since the linearity of the coordinate detection value along the first direction can be satisfactorily obtained, the detection accuracy of the first position coordinate can be improved.

A display device according to an embodiment of the present technology includes a plurality of electrode rows, a display element, and a processing unit.
Each of the plurality of electrode rows includes a first electrode, a second electrode, and a third electrode. The first electrode extends in a first direction, and a first region in which a dimension parallel to a second direction orthogonal to the first direction is gradually increased with respect to the first direction; And a second region whose dimension parallel to the second direction is gradually reduced with respect to the first direction. The second electrode extends in the first direction, opposes the first region and the second direction, and a dimension parallel to the second direction with respect to the first direction is gradually reduced. Become. The third electrode extends in the first direction, opposes the second region with the second direction, and is gradually larger in dimension parallel to the second direction with respect to the first direction. Become. In the plurality of electrode arrays, a set of the first electrode, the second electrode, and the third electrode is arranged in the second direction, and the capacitance is increased according to the proximity of the detection target. Configured to change.
The display element has a display surface facing the plurality of electrode rows.
The processing unit includes a first value that is a sum of capacitance values of the first electrodes in each of the plurality of electrode rows and a sum of capacitance values of the second electrodes in each of the plurality of electrode rows. A value of 2; a third value that is a sum of capacitance values of the third electrodes of each of the plurality of electrode rows; and a sum of the first value, the second value, and the third value. The fourth value is calculated. When the second value is greater than the third value, the processing unit has a first ratio that is a ratio of the difference between the first value and the second value and the fourth value. The first position coordinate is detected based on the capacity ratio. When the second value is smaller than the third value, the processing unit is a ratio of a difference between the third value and the first value and a fourth value. The first position coordinate is detected based on the capacity ratio.

  According to the present technology, it is possible to reduce the influence of the size of the detection target and improve the detection accuracy of the position coordinates.

1 is an exploded perspective view schematically showing a coordinate detection device according to an embodiment of the present technology. 1 is a schematic plan view of a capacitance sensor according to an embodiment of the present technology. It is a top view which shows the structure of the electrode row | line | column of the said electrostatic capacitance sensor. It is a figure explaining one effect | action of the said coordinate detection apparatus. It is a flowchart explaining one effect | action of the said coordinate detection apparatus. It is a top view of the electrode row explaining the example of 1 operation with respect to the said coordinate detection apparatus. It is a schematic diagram which shows the capacity | capacitance change example of the electrode row | line | column with respect to the operation example shown in FIG. It is a top view of the electrode row explaining the example of 1 operation with respect to the said coordinate detection apparatus. It is a flowchart explaining one effect | action of the said coordinate detection apparatus. It is a figure explaining one effect | action of the said coordinate detection apparatus, and its comparative example. It is a figure explaining one effect | action of the said coordinate detection apparatus. It is a figure explaining one effect | action of the said coordinate detection apparatus. It is a top view which shows the other structural example of the said electrostatic capacitance sensor. It is a top view of the capacitive sensor explaining other embodiments of this art. It is a figure explaining an effect | action of the coordinate detection apparatus which concerns on one Embodiment of this technique. It is a figure explaining an effect | action of the coordinate detection apparatus which concerns on one Embodiment of this technique. It is a figure explaining an effect | action of the coordinate detection apparatus which concerns on one Embodiment of this technique. It is a figure explaining an effect | action of the coordinate detection apparatus which concerns on one Embodiment of this technique. It is a figure explaining the modification of the coordinate detection apparatus which concerns on one Embodiment of this technique.

  Hereinafter, embodiments of the present technology will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is an exploded perspective view illustrating a schematic configuration of a coordinate detection device according to an embodiment of the present technology. The coordinate detection device 100 of this embodiment is incorporated in a screen display unit of various electronic devices such as a portable information terminal, a digital camera, a video camera, a personal computer, and a car navigation system, and constitutes a display device as a user interface. .

[Coordinate detector]
The coordinate detection device 100 includes a capacitance sensor 1, a display element 17, a drive unit 18, and a control unit 19. In addition, illustration of the housing | casing which accommodates the electrostatic capacitance sensor 1, the display element 17, etc. is abbreviate | omitted.

  FIG. 2 is a plan view schematically showing the configuration of the capacitance sensor 1. The capacitance sensor 1 has a detection area A. The capacitance sensor 1 is installed on the operation surface 17a of the display element 17, and is configured as a sensor panel that detects the proximity or contact of a detection target (for example, a user's finger) in the detection area A based on a change in capacitance. Is done. 1 and 2, the X axis is an axis parallel to the horizontal direction of the operation screen 17a, the Y axis is an axis parallel to the vertical direction of the operation screen 17a, and the Z axis is an axis perpendicular to the operation screen 17a. Show.

As shown in FIG. 2, the capacitance sensor 1 has a plurality of electrode arrays 10 ₁ , 10 ₂ , 10 ₃ , 10 ₄ ,..., 10 _N and a support 14 that supports these electrode arrays. . Each electrode row is arranged on the surface of the support 14 at a constant pitch along the Y-axis direction. In FIG. 2, each electrode row is indicated as electrode rows 10 ₁ , 10 ₂ , 10 ₃ , 10 ₄ ,..., 10 _{N in} order along the + Y direction (second direction). In the present specification, each electrode row is generically referred to as “electrode row 10” unless otherwise described.

  As shown in FIG. 2, the electrode array 10 includes a set of a first electrode 11, a second electrode 12, and a third electrode 13. In the present embodiment, the electrode array 10 has a structure in which a rectangle having a length S and a width W is divided into a first electrode 11, a second electrode 12, and a third electrode 13 extending in the X-axis direction. Have. Here, the length S indicates the length dimension of the electrode array 10 along the X-axis direction, and the width W indicates the width dimension of the electrode array 10 along the Y-axis direction. FIG. 3 is an enlarged plan view showing a set of electrode rows 10.

  The first electrode 11 has a base 11a parallel to the X-axis direction, and its length S is substantially equal to the lateral dimension of the detection area A. That is, the first electrode 11 has a length dimension that covers the lateral dimension of the detection area A along the X-axis direction.

  The first electrode 11 includes a first region 111 in which the width dimension parallel to the + Y direction is gradually increased in the length direction parallel to the + X direction, and a second region 112 in which the width dimension is gradually decreased in the + X direction. And have. In the present embodiment, the first electrode 11 is formed in a substantially isosceles triangle having two oblique sides 11b and 11c that form the maximum value of the width dimension at the center in the length direction.

  The second electrode 12 faces the first region 111 in the Y-axis direction, and is formed so that the width dimension parallel to the + Y direction gradually decreases with respect to the + X direction. In the present embodiment, the second electrode 12 includes a base 12 a that is parallel to the base 11 a of the first electrode 11 and is approximately half the length of the base 11 a, and a hypotenuse 12 b that faces the hypotenuse 11 b of the first electrode 11. And a right-angled triangle having adjacent sides 12c adjacent thereto. The hypotenuse 11b of the first electrode 11 and the hypotenuse 12b of the second electrode 12 have the same tilt angle with respect to the X-axis, and there is a certain size between the two hypotenuses 11b and 12b. A gap is provided. The size of the gap is not particularly limited as long as the gap can ensure electrical insulation between the first region 111 and the second electrode 12.

  The third electrode 13 faces the second region 112 in the Y-axis direction, and is formed so that the width dimension parallel to the + Y direction gradually increases with respect to the + X direction. In the present embodiment, the third electrode 13 is parallel to the base 11 a of the first electrode 11 and has a base 13 a that is approximately half the length of the base 11 a and a hypotenuse 13 b that faces the hypotenuse 11 c of the first electrode 11. And a right-angled triangle having adjacent sides 13c adjacent thereto. The hypotenuse 11c of the first electrode 11 and the hypotenuse 13b of the second electrode 12 have the same inclination angle with respect to the X-axis, and a certain size is provided between the two hypotenuses 11c and 13b. A gap is provided. The size of the gap is not particularly limited as long as the gap can ensure electrical insulation between the second region 112 and the third electrode 13.

  The second electrode 12 and the third electrode 13 are opposed to each other in the X-axis direction with a gap therebetween, and are symmetrical with respect to a straight line passing through the center of the first electrode 11 and parallel to the Y-axis direction. have.

  The support 14 is disposed to face the image display surface (operation screen 17a) of the display element 17. The support base material 14 supports the plurality of electrode arrays 10 configured as described above, and maintains a state in which each electrode array 10 is arranged at a predetermined pitch in the Y-axis direction. The support 14 is formed of a flexible electrically insulating plastic film such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PI (polyimide), and PC (polycarbonate). In addition, rigid materials such as glass and ceramics may be used.

  Moreover, the support body 14 may be comprised by the laminated body of a plastic film, a glass substrate, etc. In this case, for example, each electrode row 10 is formed on one surface of a plastic film, and a glass substrate is laminated on the other surface of the plastic film via an adhesive layer.

  The electrode array 10 (first to third electrodes 11 to 13) and the support 14 are each formed of a light-transmitting material. For example, the electrode array 10 is formed of a transparent conductive oxide such as ITO (indium tin oxide), SnO, or ZnO, and the support 14 is formed of a transparent resin film such as PET or PEN. Thereby, the display image of the operation screen 17a can be visually recognized from the outside via the capacitance sensor 1.

  The method for forming the electrode array 10 is not particularly limited. For example, the conductive film for forming the electrode array 10 is formed on the support 14 by using a thin film formation method such as vapor deposition, sputtering, or CVD. In this case, after forming the conductive film on the substrate, the conductive film may be patterned into a predetermined shape, or after forming the conductive film on the surface of the substrate on which the resist mask is formed, an extra conductive film is formed together with the resist mask. May be removed (lifted off) from the substrate. In addition to this, the electrode pattern may be formed on the substrate using a printing method such as plating or screen printing.

  The electrode array 10 further includes a signal line (wiring) for connecting the first to third electrodes 11 to 13 to the driving unit 18. In the present embodiment, as shown in FIG. 3, the signal line 11 s is connected to one end in the length direction of the first electrode 11, and outside the detection area A of the second electrode 12 and the third electrode 13. Signal lines 12s and 13s are connected to the facing sides 12c and 13c, respectively.

  The signal lines 11 s to 13 s are routed in a region outside the detection area A on the support 14 and are connected to the drive unit 18 via an external connection terminal such as a connector (not shown). The signal lines 11 s to 13 s are formed independently for each electrode row 10 of each row, and are connected to the drive unit 18 in common.

  The signal lines 11 s to 13 s may be formed of a constituent material of the electrode array 10. In this case, the signal lines 11 s to 13 s can be formed simultaneously with the formation of the electrode array 10. On the other hand, the signal lines 11s to 13s may be formed of a non-translucent conductive material, for example, a metal wiring such as Al (aluminum), Ag (silver), Cu (copper). In this case, since the wiring layer can be made of a material having a low specific resistance, it is possible to detect a change in capacitance of the electrode array 10 with high sensitivity. Further, in this case, since the signal lines 11s to 13s are located outside the detection area A, when the outside of the detection area A is outside the effective pixel area of the operation screen 17a, the image visibility is the signal line 11s. It is not inhibited by ~ 13s.

  The length S of the electrode array 10 is set according to the horizontal dimension of the detection area A. The length S of the electrode array 10 may be equal to the horizontal dimension of the detection area A, or may be larger or smaller than that. In short, the single electrode array 10 is formed to a size that can cover the entire width of the detection area A, and is configured such that two or more electrode arrays 10 are not arranged in parallel in the X-axis direction.

  On the other hand, the width W of the electrode array 10 is appropriately set according to the vertical dimension of the detection area A, the size of the detection target, the detection resolution in the Y-axis direction, and the like. In this embodiment, a user's finger is assumed as a detection target, and is set to, for example, 5 mm to 10 mm in consideration of the size of the finger in contact with the operation surface. Similarly, the number of electrode rows 10 arranged along the Y-axis direction is not particularly limited, and is appropriately set according to the vertical dimension of the detection area A, the size of the detection target, the detection resolution in the Y-axis direction, and the like.

  Further, as shown in FIG. 3, the sum of the width dimension of the first electrode 11 and the width dimension of the second and third electrodes 12 and 13 is constant in the + X direction. Thereby, since the height dimension of the whole electrode row | line | column can be made constant, generation | occurrence | production of the variation in the detection sensitivity according to the position of the detection target regarding an X-axis direction can be suppressed.

  Furthermore, as shown in FIG. 1, the capacitance sensor 1 has a protective layer 15 that covers the surface of each electrode array 10. The protective layer 15 is made of a resin film such as PET or PEN having translucency, a plastic plate, a glass plate, or the like. And the outermost surface of the protective layer 15 comprises the operation surface touch-operated by the user.

[Drive part]
The drive unit 18 that drives each electrode array 10 includes a signal generation circuit that generates a signal voltage supplied to each of the electrodes 11 to 13, and an arithmetic circuit that calculates the capacitance of the electrodes 11 to 13 and changes thereof. . The signal voltage is not particularly limited as long as it is a signal that can oscillate the electrodes 11 to 13. For example, a pulse signal of a predetermined frequency, a high-frequency signal, an AC signal, or a DC signal can be used. The arithmetic circuit is not particularly limited as long as it is a circuit that can detect the capacitance of the oscillation electrode or the amount of change thereof. The arithmetic circuit of the present embodiment converts the capacitance value into an integer value (count value) and outputs it to the control unit 19. The capacitance value may be the capacitance of the electrode or the amount of change in capacitance.

  In the present embodiment, the capacitance of each of the electrodes 11 to 13 and the amount of change thereof are detected by a so-called self capacitance method. The self-capacitance method is also called a single electrode method, and one electrode is used for sensing. The sensing electrode has a stray capacitance with respect to the ground potential, and the stray capacitance of the electrode increases as a grounded detection target such as a human body (finger) approaches. The arithmetic circuit calculates the proximity of the fingers and the position coordinates by detecting this increase in capacity.

  The oscillation order of the electrodes 11 to 13, that is, the scanning method is not particularly limited, and may sequentially oscillate in the width direction (+ X direction) or sequentially in the opposite direction (−X direction). In addition, a method of oscillating each column simultaneously may be employed between the electrode columns, or a method of oscillating each column sequentially (for example, in the Y direction) may be employed.

  Further, the method is not limited to the method of always oscillating all the electrodes 11 to 13 of each electrode row 10, and it is also possible to oscillate by thinning out predetermined electrodes. For example, only the first electrode 11 in each column (or at a predetermined interval) is oscillated until the proximity of a detection target (such as a user's finger) is detected, and the number of oscillation electrodes increases as the detection target approaches. You may let them. It is also possible to select an oscillation electrode according to the display form of the operation screen 17a. For example, when an image that requires an input operation with a finger is unevenly distributed on the left side of the screen, only the second electrode 12 in each column may be scanned, or the image is unevenly distributed on the right side of the screen. In some cases, only the third electrode 13 in each column may be scanned. Thereby, compared with the case where all the electrodes are scanned, the electrode required for a drive can be reduced.

[Control unit]
Based on the output of the drive unit 18, the control unit 19 generates a control signal for controlling an image displayed on the operation screen 17 a of the display element 17 and outputs the control signal to the display element 17. The control unit 19 is typically configured by a computer, specifies a finger operation position, an operation direction, and the like in the detection area A, and performs predetermined image control corresponding thereto. For example, control of the screen in accordance with the user's intention, such as changing the image on the screen corresponding to the operation position or moving the image along the operation direction, is executed.

  The control unit 19 may further generate other control signals for controlling other functions of the coordinate detection device 100. For example, depending on the operation position on the operation screen 17a, execution of various functions such as a call function, a line switching function, a dictionary function, an input function such as character information, and a game function may be mentioned.

  The control unit 19 is not limited to an example configured with a circuit separate from the drive unit 18, and may be configured with a circuit integrated with the drive unit 18. For example, the control unit 19 and the drive unit 18 can be configured by a single semiconductor chip (IC chip). The drive unit 18 and the control unit 19 constitute a processing unit of the coordinate detection apparatus 100.

[Operation example of coordinate detection device]
Next, an operation example of the coordinate detection apparatus 100 will be described. Here, a method for detecting the input operation position (XY coordinates) of the finger using the capacitance sensor 1 will be described. As described above, the input operation position is determined by the control unit 19.

  FIG. 4 is a schematic diagram illustrating an example of a coordinate detection method using the capacitance sensor 1. The capacitance sensor 1 is driven by the drive unit 18 and outputs a change in capacitance according to the position and movement of the user's finger F (detection target) to the drive unit 18. The drive unit 18 converts the capacitance value output from each electrode 11 to 13 of the capacitance sensor 1 into a count value, and outputs it to the control unit 18. Based on the count values of the electrodes 11 to 13, the control unit 19 detects the X coordinate and the Y coordinate of the finger F by a calculation method as described later.

Hereinafter, for each electrode row, the first electrode 11 located in the center is the electrodes C ₁ , C ₂ , C ₃ , C ₄ , and the second electrode 12 located on the left side is the electrodes L ₁ , L ₂ , L ₃ , L ₄ and the third electrode 13 located on the right side are denoted as electrodes R ₁ , R ₂ , R ₃ and R ₄ , respectively. The capacitance sensor 1 has four electrode rows Y ₁ , Y ₂ , Y ₃ and Y ₄ , and the center of the finger F is located between the electrode L ₃ and the electrode C ₃ . As a result, an example of the count value of each electrode calculated by the drive unit 18 is shown in FIG.

(Detection of Y coordinate)
In the capacitance sensor 1, each of the electrode arrays 10 constitutes one detection group. Therefore, the proximity or contact of the detection target is detected based on the sum of the capacitance values of the electrodes L, C, and R constituting the electrode array 10 as the operation position in the Y-axis direction. The control unit 19 calculates the total of the capacitance changes of the electrodes L, C, R in each of the plurality of electrode rows (ΣYn (n is a column number)), and based on these values, Y of the finger F Detect coordinates.

FIG. 5 is a flowchart for explaining a method of detecting the Y coordinate. First, the control unit 19 adds up the count values of the electrode arrays (ST11). Next, the control unit 19 sets the center positions (Y ₁ c, Y ₂ c, Y ₃ c, Y ₄ c) of the electrode rows Y ₁ , Y ₂ , Y ₃ , Y ₄ and the count sum (ΣY ₁ , ΣY _2). , ΣY ₃ , ΣY ₄ ), the center of gravity of the Y position is calculated by the following calculation formula, and the Y coordinate of the finger F is detected (ST12, ST13).
Y position = (ΣY ₁・ (Y ₁ c) + ΣY ₂・ (Y ₂ c) + ΣY ₃・ (Y ₃ c) + ΣY ₄・ (Y ₄ c))
/ (ΣY ₁ , ΣY ₂ , ΣY ₃ , ΣY ₄ ) (1)

Here, the center position of the electrode row corresponds to the Y coordinate of the center portion of each electrode row, and here Y ₁ c = 2 (mm), Y ₂ c = 6 (mm), Y ₃ c = 10 (mm ), Y ₄ c = 14 (mm). Substituting these values into equation (1), the Y position is ((0x14) + (1x10) + (10x6) + (3x2)) / (0 + 1 + 10 + 3) = 5.42 (mm) is detected.

(X coordinate detection)
Next, changes in the capacitances of the electrodes L, C, and D when the finger F is moved at a constant speed along the + X direction immediately above an arbitrary electrode row 10 as shown in FIG. 6 will be described. . Figure 7 (A) is the capacitance of the electrode L (count value) time variation of C _L, FIG. 7 (B) is the capacitance of the electrode C (count value) time variation of the C _C, FIG. 7 (C) is time change of the electrostatic capacitance (count value) C _R electrode R to indicate respectively.

  Consider a case where the finger F moves from the position indicated by the alternate long and short dash line in FIG. 6 toward the center in the length direction (X-axis direction) of the electrode array 10. The electrode C has a first region 111 whose width dimension gradually increases in the + X direction, and the electrode L is formed so that the width dimension gradually decreases in the + X direction. Accordingly, as the finger F moves in the + X direction, the overlapping region between the finger F and the electrode C (first region 111) gradually increases, but the overlapping region between the finger F and the electrode L gradually decreases. Since the value of the capacitance is substantially proportional to the size of the overlapping area with the finger F, the capacitance of the electrode C gradually increases as shown in FIG. 7B, and at the longitudinal center position (Xc). The maximum value is reached. On the other hand, as shown in FIG. 7A, the capacitance of the electrode L gradually decreases and takes a minimum value at the longitudinal center position (Xc). Meanwhile, since the electrode R does not overlap with the finger F, the change in the capacitance is zero.

  Similarly, consider the case where the finger F moves from the center in the length direction of the electrode array 10 to the position indicated by the solid line in FIG. The electrode C has a second region 112 whose width dimension gradually decreases in the + X direction, and the electrode R is formed so that the width dimension gradually increases in the + X direction. Therefore, as the finger F moves in the + X direction, the overlapping region between the finger F and the electrode C (second region 112) gradually decreases, but the overlapping region between the finger F and the electrode R gradually increases. As a result, the capacitance of the electrode C gradually decreases as shown in FIG. 7B, and conversely, the capacitance of the electrode R gradually increases as shown in FIG. 7C. Meanwhile, since the electrode L does not overlap with the finger F, the change in the capacitance is zero.

  In this embodiment, since the width dimension of the electrode array 10 is constant in the length direction, the detection sensitivity of the finger F can be made constant in the X-axis direction regardless of the operation position of the finger F. In addition, since the electrode C is formed in an isosceles triangle shape and the electrodes L and R have symmetrical shapes, the detection sensitivity varies between the first region 111 side and the second region 112 side. Can be eliminated. Thereby, the operation position of the finger F in the X-axis direction can be detected with high accuracy.

  In the present embodiment, the boundary between the electrode C and the electrode L and the boundary between the electrode C and the electrode R are formed by linear hypotenuses 11b, 11c, 12b, and 13b, respectively. Thereby, it is possible to provide a predetermined proportional relationship between the position of the detection target along the X-axis direction and the capacitance ratio between the respective electrodes, thereby ensuring stable detection sensitivity.

  Next, a method for calculating the X coordinate by the control unit 19 will be described.

In the present embodiment, the control unit 19 includes the sum (ΣC) of the capacitance values of the electrodes C (C ₁ , C ₂ , C ₃ , C ₄ ) of each electrode row 10 and the electrodes L (L ₁ of each electrode row 10). , L ₂ , L ₃ , L ₄ ) and the sum (ΣR) of the capacitance values of the electrodes R (R ₁ , R ₂ , R ₃ , R ₄ ) of each electrode array 10, The sum of the capacitance values of these electrodes (ΣLCR (= ΣL + ΣC + ΣR)) is calculated. When ΣL is larger than ΣR, the control unit 19 detects the X coordinate of the finger F based on the first capacity ratio (P1) which is the ratio of the difference between ΣC and ΣL and ΣLCR. On the other hand, when ΣL is smaller than ΣR, the control unit 19 detects the X coordinate of the finger F based on the second capacity ratio (P2) which is the ratio of the difference between ΣR and ΣC and ΣLCR.

  8A to 8C are schematic diagrams of the capacitance sensor showing the magnitude relationship between ΣL and ΣR depending on the operation position of the finger F. FIG. As described above, when the finger F is detected, the sum of the capacitance values of the individual electrodes L, C, and R and the sum of the capacitance values of all the electrodes L, C, and R in the plurality of electrode rows 10 are referred to. In the self-capacitance type capacitance sensor, when the finger F is located on the left side of the operation area, ΣL> ΣR (FIG. 8A), and the finger F is located on the right side of the operation area. ΣL <ΣR (FIG. 8C). On the other hand, when the finger F is located at the center of the operation area, ΣL≈ΣR (FIG. 8B).

FIG. 9 is a flowchart for explaining an X coordinate detection method. First, the control unit 19 calculates the sum (ΣL, ΣC, ΣR) of the capacitance values for the electrodes L, C, R in each column (ST21). Next, the control unit 19 compares the magnitudes of ΣL and ΣR (ST22). When ΣL> ΣR, the control unit 19 calculates the first capacity ratio P1 by the following equation (2) and detects the X coordinate of the finger F (ST23, ST26). On the other hand, when ΣL <ΣR, the control unit 19 calculates the second capacity ratio P2 by the following equation (3) and detects the X coordinate of the finger F (ST24, 26). Further, when ΣL = ΣR, the control unit 19 determines that the finger F is at the center in the length direction (X-axis direction) of the electrode C, and uses it as the X coordinate (ST25, ST26).
P1 = (ΣC−ΣL) / ΣLCR (2)
P2 = (ΣR−ΣC) / ΣLCR (3)

  In the present embodiment, since the X coordinate is detected based on the first capacity ratio P1 and the second capacity ratio P2 that are selectively used according to the magnitude relationship between ΣL and ΣR, the X axis direction is detected. Therefore, the linearity of the detected coordinate value can be obtained well, and the detection accuracy of the X coordinate can be improved.

  FIGS. 10A and 10B show examples of detected values of the X coordinate calculated by two coordinate detection methods having different calculation methods. FIG. 10A shows the X coordinate value calculated based on the difference between the capacitance values of the two predetermined electrodes as in this embodiment, and FIG. 10B shows the ratio of the capacitance values of the two predetermined electrodes. The X coordinate value calculated based on is shown. As is apparent from the results of FIGS. 10A and 10B, the present embodiment provides better linearity of the count value along the X-axis direction.

  In the present embodiment, a predetermined threshold value may be set when calculating ΣL−ΣR. That is, when the difference between ΣL and ΣR exceeds the first threshold (A1) (ΣL−ΣR> A1), the control unit 19 detects the X coordinate based on the first capacity ratio P1, and ΣL and ΣR The X coordinate may be detected based on the second capacity ratio P2 when the difference between and is less than the second threshold value (A2) smaller than the first threshold value (ΣL−ΣR <A2). In this case, when the difference between ΣL and ΣR is not less than the second threshold value (A2) and not more than the first threshold value (A1) (A2 ≦ ΣL−ΣR ≦ A1), the X coordinate is the center in the length direction of the electrode C. Part.

  As a result, variations in coordinate values due to detection errors in the count value can be suppressed, and detection accuracy can be improved. The magnitudes of the thresholds A1 and A2 are not particularly limited, and can be set as appropriate according to the shape and size of the electrodes, the detection resolution of the count value, and the like. Further, the magnitude relationship between the thresholds A1 and A2 is not particularly limited, and for example, A2 = −A1 can be set.

  In the present embodiment, as shown in FIG. 11A, the transition of the count value between the first capacitance ratio P1 and the second capacitance ratio is discontinuous at the longitudinal center position Xc of the electrode C. Therefore, the control unit 19 sets the first capacitance ratio P1 and the second capacitance ratio so that the first capacitance ratio P1 and the second capacitance ratio P2 at the center position Xc of the electrode C in the X-axis direction are the same. An offset coefficient is added to at least one of P2. Thereby, the continuity of the X coordinate is obtained in the length direction of the electrode array 10.

  The offset coefficient only needs to be large enough to cancel the difference B between the count values of the first capacitance ratio P1 and the second capacitance ratio P2 at the Xc position shown in FIG. It may be added to the calculation formula for the capacity ratio of 1, or may be added to the second capacity ratio P2 as shown in FIG. Alternatively, when B = b1 + b2, the first coefficient b1 may be added to the first capacity ratio P1, and the coefficient b2 may be added to the second capacity ratio P2.

  Further, the count value of the capacitance value is affected by the facing area between the electrode array 10 and the finger F. 12A to 12C show an example of the relationship between the size of the finger F and the capacitance difference between the electrodes (ΣC−ΣL, ΣR−ΣC). Here, the capacitance difference between the electrodes was calculated from the capacitance change when the tips of the metal rods having diameters of 8 mm, 10 mm and 12 mm were moved along the longitudinal direction of the electrode array 10. As shown in FIG. 12, it can be seen that the larger the facing area between the electrode array 10 and the metal rods, the larger the rate of change in capacitance difference between electrodes (straight line).

  In the present embodiment, when calculating the capacitance ratios P1 and P2, the capacitance difference between the electrodes is divided by the total count value (ΣLCR) of all the electrodes, so compared with the case of only the capacitance difference between the electrodes, The change in the change rate of the capacity difference due to the difference in the facing area from the detection target is small. That is, by dividing the capacitance difference between the electrodes by ΣLCR, the size of the detection target can be standardized, thereby reducing the influence of the size of the detection target and enabling highly accurate coordinate detection.

Further, the control unit 19 multiplies the ΣLCR by a correction coefficient for suppressing change rate variation of the first and second capacitance ratios P1 and P2 based on the facing areas of the plurality of electrode rows 10 and the fingers F, The detection value of the X coordinate may be corrected. Thereby, it is possible to make the capacity change rate constant for detection objects of different sizes. An example of the arithmetic expression is shown below.
P1 = (ΣC−ΣL) / (ΣLCR · d1) + b1 (4)
P2 = (ΣR−ΣC) / (ΣLCR · d2) + b2 (5)

  Here, the correction coefficients d1 and d2 may be the same value or different values. The correction coefficients d1 and d2 may be values greater than 1 or numerical values less than 1. The correction coefficients d1 and d2 can be determined based on the rate of change of the capacity ratios P1 and P2 using a plurality of detection targets having different sizes. B1 and b2 are the offset coefficients described above.

In calculating the first capacity ratio P1, ΣR is often substantially unnecessary. Therefore, a correction term for ΣR may be added when calculating the first capacity ratio P1. Similarly, a correction term of ΣL may be added when calculating the second capacity ratio P2. An example of those calculation formulas is shown below.
P1 = (ΣC−ΣL−ΣR) / (ΣLCR · d1) + b1 (6)
P2 = (ΣL + ΣR−ΣC) / (ΣLCR · d2) + b2 (7)

[Experimental example]
The inventors determined the offset coefficients b1 and b2 and the correction coefficients d1 and d2 in the equations (6) and (7) using the electrostatic capacitance sensor having the electrode structure shown in FIG. The illustrated electrostatic capacitance sensor 2 has a configuration in which an electrode array 20 including a set of an electrode C, an electrode L, and an electrode R is arranged in the Y-axis direction. Here, the capacitance sensor 2 has a size that can be applied to a 3-inch wide display unit, and each electrode is formed by etching the ITO layer of the ITO film. The number of arrangement of the electrode rows 20 was seven.

  Electrodes C, L, and R correspond to electrodes 11, 12, and 13 shown in FIG. Each electrode C, L, R has two-stage electrode portions Ca, Cb, La, Lb, Ra, Rb adjacent in the Y-axis direction, and each electrode portion is arranged in a staggered combination between the electrodes. Yes.

In the experiment, a φ8 mm metal rod grounded to the ground is placed immediately above the electrode row 20 and moved at a constant speed in the + X direction, and the capacitance of each electrode L, C, R at a predetermined plot position along the X axis direction. The values were measured, and ΣL, ΣC, and ΣR at each plot position were calculated. Similarly, ΣL, ΣC, and ΣR at each plot position were calculated for φ10 mm and 12 mm metal bars. Then, average values of ΣL, ΣC, and ΣR of φ8 mm, φ10 mm, and φ12 mm metal rods were calculated, respectively, and correction values d1 and d2 and offset coefficients b1 and b2 were determined as shown in the following equations.
P1 = (ΣC−ΣL−ΣR) / (ΣLCR / 60) −479 (6) ′
P2 = (ΣL + ΣR−ΣC) / (ΣLCR / 60) +483 (7) ′

<Second Embodiment>
Next, another embodiment of the present technology will be described. FIG. 14 is a schematic plan view of the capacitance sensor 3 according to the present embodiment. Hereinafter, configurations different from those of the first embodiment will be mainly described, and configurations similar to those of the above-described embodiment will be denoted by the same reference numerals, and description thereof will be omitted or simplified.

  The capacitance sensor 3 of the present embodiment has an electrode array 30 configured by a set of a first electrode 31 and a second electrode 32. The electrode array 30 is arranged on the support 14 in the Y-axis direction. The first electrode 31 has a right triangle shape that extends in the X-axis direction and has a width dimension that gradually increases in parallel to the Y-axis direction with respect to the + X direction. The second electrode 32 extends in the X-axis direction and has a right triangle shape such that the width dimension parallel to the Y-axis direction gradually decreases with respect to the + X direction. The hypotenuses of the first and second electrodes 31 and 32 are opposed to each other in the Y-axis direction.

  The capacitance sensor 3 is driven by the drive unit 18 (FIG. 1). The drive unit 18 detects a change in capacitance of each electrode array 30 according to the proximity of the detection target, and outputs the change to the control unit 19 (FIG. 1). The control unit 19 adds the sum (ΣL) of the capacitance values of the first electrodes 31 (L) of each electrode row 30 and the sum (ΣR) of the capacitance values of the second electrodes 32 (R) of each electrode row 30. The sum of the capacitance values of these electrodes (ΣLR (= ΣL + ΣR)) is calculated. Then, the control unit 19 detects the X coordinate of the finger F based on the difference between ΣL and ΣR and the capacity ratio between ΣLR.

  In this embodiment, since the X coordinate is detected based on the value of (ΣL−ΣR) / ΣLR, the linearity of the coordinate detection value along the X-axis direction can be obtained satisfactorily, and the X coordinate is detected. Accuracy can be improved.

  On the other hand, when detecting the Y coordinate, the control unit 19 calculates the sum (ΣLR) of the capacitance value (ΣL) of the electrode L and the capacitance value (ΣR) of the electrode R in each electrode row 30, and based on them. The Y coordinate of the detection target along the Y-axis direction is detected. In this case, weighting may be performed at the center position of each electrode row 30 as in the first embodiment described above.

  As mentioned above, although embodiment of this technique was described, this technique is not limited only to the above-mentioned embodiment, Of course, in the range which does not deviate from the summary of this technique, various changes can be added.

In the X-coordinate detection method based on the first and second capacity ratios described in the first embodiment, correction for improving the linearity of each capacity ratio may be performed by the control unit 19. Examples of such correction equations include the following.
P1 = (((p · ΣC) −ΣL−ΣR / q)) / ((ΣL + (p · ΣC) + ΣR) · d1) + b1) + s (8)
P2 = (((ΣL / r) + ΣR− (p · ΣC)) / ((ΣL + (p · ΣC) + ΣR) · d2) + b2) + s (9)

  Here, p is a correction coefficient for adjusting the strength of ΣC. Since the linearity deteriorates when the sensitivity of the electrode C is relatively low due to the pattern shape, the resistance value of the electrode constituent material, etc., the linearity can be improved by adjusting the count value of ΣC. The linear characteristic before the correction is shown in FIG. 15A, and the linear characteristic after the correction is shown in FIG. 15B.

  Further, q and r are correction coefficients for suppressing deterioration of linearity due to an increase in unnecessary count value due to the size of the detection target. For example, as shown in FIGS. 16A and 16B, as the area facing the finger F increases, the count value of ΣR unnecessary for calculation increases. On the other hand, if the value of the correction term (−ΣR, + ΣL) inserted to delete the count value unnecessary for the calculation is large, a bending point appears at the Xc position as shown in FIG. Therefore, by inserting the optimized correction coefficients q and r, it is possible to ensure high linearity at the Xc position as shown in FIG.

  S is a correction coefficient for processing the values of the calculated capacity ratios P1 and P2 with positive values. FIG. 18A shows the capacitance ratios P1 and P2 before the correction, and FIG. 18B shows the capacitance ratios P1 and P2 after the correction.

  On the other hand, in each of the above embodiments, by dividing the difference in the capacitance value between the electrodes by the count value (ΣLCR or ΣLR) of all the electrodes, the variation in the value of the capacitance ratio due to the size of the detection target is reduced. However, such a calculation is effective not only for the size of the detection target, but also for reducing calculation variations caused by the temperature characteristics of the capacitance sensor 1, the drive unit 18, the control unit 19, and the like.

  Furthermore, in the above embodiment, the X-axis direction is set to the longitudinal direction of the electrode array, and the Y-axis direction is set to the array direction of the electrode array. However, as shown in FIG. In addition, the Y-axis direction may be set in the longitudinal direction of the electrode array 20. FIG. 19 shows a configuration of the electrode array 20 shown in FIG. 13 as a configuration example of the electrode array.

In FIG. 19, the coordinate in the Y direction can be obtained by adding ΣLINE (n) (n is a line number) × line centroid. Specifically, a value corresponding to the coordinate in the Y direction can be obtained by the following equation.
Y = Y1 × ΣLINE (1) + Y2 × ΣLIINE (2) + ... + Y7 × ΣLINE (7) (10)

Furthermore, the coordinate calculation result in the X direction can be corrected based on the calculation result of the Y coordinate. For example, when a periodic coordinate shift occurs in the Y direction, the calculation result can be corrected in the opposite direction of the periodic coordinate shift by the value of β calculated by the following calculation formula.
β = α · Sin (2y / (a × π) + π / 2) (11)
Here, β is a cycle correction value in the X-axis direction, y is a calculated coordinate value in the Y-axis direction, α is a maximum correction amount, and a is a pitch amount corresponding to a cycle in the Y-axis direction.

In addition, this technique can also take the following structures.
(1) a first region extending in a first direction and gradually increasing in dimension parallel to a second direction perpendicular to the first direction with respect to the first direction; and with respect to the first direction A first electrode having a second region whose dimension parallel to the second direction gradually decreases;
A second electrode extending in the first direction and facing the first region in the second direction, the dimension parallel to the second direction gradually decreasing with respect to the first direction;
A third electrode extending in the first direction and opposed to the second region in the second direction and having a dimension gradually increasing in parallel with the second direction with respect to the first direction; A pair of the first electrode, the second electrode, and the third electrode is arranged in the second direction, and outputs a capacitance value corresponding to the detection target and the distance. A plurality of configured electrode arrays; and
A first value that is a sum of capacitance values of the first electrodes of each of the plurality of electrode rows; a second value that is a sum of capacitance values of the second electrodes of each of the plurality of electrode rows; A third value that is a sum of capacitance values of the third electrodes of each of the plurality of electrode rows; a fourth value that is a sum of the first value, the second value, and the third value; Value and
When the second value is greater than the third value, based on a first capacitance ratio that is a ratio of the difference between the first value and the second value and the fourth value Detecting the first position coordinates;
When the second value is smaller than the third value, based on a second capacity ratio that is a ratio between the difference between the third value and the first value and the fourth value. A coordinate detection apparatus comprising: a processing unit that detects the first position coordinates.
(2) The coordinate detection device according to (1) above,
The processing unit is
When the difference between the second value and the third value exceeds a first threshold, the first position coordinate is detected based on the first capacity ratio;
When the difference between the second value and the third value is less than a second threshold value that is smaller than the first threshold value, the first position coordinate is detected based on the second capacitance ratio. ,
When the difference between the second value and the third value is greater than or equal to the second threshold and less than or equal to the first threshold, the first position coordinate is determined to be the central portion of the first electrode Detection device.
(3) The coordinate detection device according to (1) or (2) above,
The processing unit has a fifth value that is a sum of a capacitance value of the first electrode, a capacitance value of the second electrode, and a capacitance value of the third electrode in each of the plurality of electrode rows. A coordinate detection device that calculates each of the second position coordinates of the detection target along the second direction based on the fifth value in each of the plurality of electrode rows.
(4) The coordinate detection device according to any one of (1) to (3) above,
The processing unit includes the first capacitance ratio and the second capacitance ratio so that the first capacitance ratio and the second capacitance ratio at the center portion of the first electrode in the first direction are the same. A coordinate detection device that adds an offset coefficient to at least one of the two capacity ratios.
(5) The coordinate detection device according to any one of (1) to (4) above,
The processing unit sets a correction coefficient for suppressing a variation in the first capacitance ratio and the second capacitance ratio based on an opposing area of the plurality of electrode arrays and the detection target to the fourth value. Multiplying coordinate detection device.

DESCRIPTION OF SYMBOLS 1, 2, 3 ... Capacitance sensor 10, 20, 30 ... Electrode row 11, C ... 1st electrode 12, L ... 2nd electrode 13, R ... 3rd electrode 17 ... Display element 18 ... Drive part DESCRIPTION OF SYMBOLS 19 ... Control part 100 ... Coordinate detection apparatus 111 ... 1st area | region 112 ... 2nd area | region F ... Finger

Claims (8)

A first region extending in a first direction and gradually increasing in dimension parallel to a second direction perpendicular to the first direction with respect to the first direction; and the second region with respect to the first direction. A first electrode having a second region that gradually decreases in dimension parallel to the direction of
A second electrode extending in the first direction and facing the first region in the second direction, the dimension parallel to the second direction gradually decreasing with respect to the first direction;
A third electrode extending in the first direction and opposed to the second region in the second direction and having a dimension gradually increasing in parallel with the second direction with respect to the first direction; A pair of the first electrode, the second electrode, and the third electrode is arranged in the second direction, and outputs a capacitance value corresponding to the detection target and the distance. A plurality of configured electrode arrays; and
A first value that is a sum of capacitance values of the first electrodes of each of the plurality of electrode rows; a second value that is a sum of capacitance values of the second electrodes of each of the plurality of electrode rows; A third value that is a sum of capacitance values of the third electrodes of each of the plurality of electrode rows; a fourth value that is a sum of the first value, the second value, and the third value; Value and
When the second value is greater than the third value, based on a first capacitance ratio that is a ratio of the difference between the first value and the second value and the fourth value Detecting the first position coordinates;
When the second value is smaller than the third value, based on a second capacity ratio that is a ratio between the difference between the third value and the first value and the fourth value. A coordinate detection apparatus comprising: a processing unit that detects the first position coordinates. The coordinate detection apparatus according to claim 1,
The processing unit is
When the difference between the second value and the third value exceeds a first threshold, the first position coordinate is detected based on the first capacity ratio;
When the difference between the second value and the third value is less than a second threshold value that is smaller than the first threshold value, the first position coordinate is detected based on the second capacitance ratio. ,
When the difference between the second value and the third value is greater than or equal to the second threshold and less than or equal to the first threshold, the first position coordinate is determined to be the central portion of the first electrode Detection device. The coordinate detection apparatus according to claim 1,
The processing unit has a fifth value that is a sum of a capacitance value of the first electrode, a capacitance value of the second electrode, and a capacitance value of the third electrode in each of the plurality of electrode rows. A coordinate detection device that calculates each of the second position coordinates of the detection target along the second direction based on the fifth value in each of the plurality of electrode rows. The coordinate detection apparatus according to claim 1,
The processing unit includes the first capacitance ratio and the second capacitance ratio so that the first capacitance ratio and the second capacitance ratio at the center portion of the first electrode in the first direction are the same. A coordinate detection device that adds an offset coefficient to at least one of the two capacity ratios. The coordinate detection apparatus according to claim 1,
The processing unit sets a correction coefficient for suppressing a variation in the first capacitance ratio and the second capacitance ratio based on an opposing area of the plurality of electrode arrays and the detection target to the fourth value. Multiplying coordinate detection device. A first electrode extending in a first direction and having a dimension gradually increasing in parallel with a second direction perpendicular to the first direction with respect to the first direction;
A second electrode extending in the first direction and facing the first electrode in the second direction, the second electrode having a dimension that gradually decreases in parallel with the second direction with respect to the first direction; Each of the plurality of first electrodes and the second electrode is arranged in the second direction, and a plurality of capacitances are configured to change in accordance with the proximity of the detection target. An electrode array;
A first value that is a sum of capacitance values of the first electrodes of each of the plurality of electrode rows; a second value that is a sum of capacitance values of the second electrodes of each of the plurality of electrode rows; A third value that is the sum of the first value and the second value is calculated, respectively, and based on a ratio between the difference between the first value and the second value and the third value. And a processing unit that detects a first position coordinate of the detection target along the first direction. The coordinate detection device according to claim 6,
The processing unit calculates a fourth value that is a sum of a capacitance value of the first electrode and a capacitance value of the second electrode in each of the plurality of electrode rows, and the plurality of electrode rows A coordinate detection device that further detects a second position coordinate of a detection target along the second direction based on the fourth value in each column of the coordinate detection device. A first region extending in a first direction and gradually increasing in dimension parallel to a second direction perpendicular to the first direction with respect to the first direction; and the second region with respect to the first direction. A first electrode having a second region that gradually decreases in dimension parallel to the direction of
A second electrode extending in the first direction and facing the first region in the second direction, the dimension parallel to the second direction gradually decreasing with respect to the first direction;
A third electrode extending in the first direction and opposed to the second region in the second direction and having a dimension gradually increasing in parallel with the second direction with respect to the first direction; A set of the first electrode, the second electrode, and the third electrode arranged in the second direction so that the capacitance changes according to the proximity of the detection target. A plurality of electrode arrays configured in
A display element having a display surface facing the plurality of electrode rows;
A first value that is a sum of capacitance values of the first electrodes of each of the plurality of electrode rows; a second value that is a sum of capacitance values of the second electrodes of each of the plurality of electrode rows; A third value that is a sum of capacitance values of the third electrodes of each of the plurality of electrode rows; a fourth value that is a sum of the first value, the second value, and the third value; Value and
When the second value is greater than the third value, based on a first capacitance ratio that is a ratio of the difference between the first value and the second value and the fourth value Detecting the first position coordinates;
When the second value is smaller than the third value, based on a second capacity ratio that is a ratio between the difference between the third value and the first value and the fourth value. And a processing unit that detects the first position coordinates.

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